flutter_pay_upi 0.2.1

Create app with UPI (Unified Payments Interface)

flutter_pay_upi

This plugin helps you add UPI (Unified Payments Interface) options to your Android and iOS apps. With this plugin, you can enable transactions to any business UPI ID within your app.

To see exactly how to use this plugin, check out the example in the "Example" section or visit the plugin's Github repository.

Check the Supported apps here.

Screenshots

Important Note

Apps like Google Pay, PhonePe, and Paytm might not be able to complete your transaction right now. They could show errors like "Maximum limit exceeded" or "Risk threshold exceeded." This could happen if you're trying to send money to someone's personal UPI (Unified Payments Interface) account. Another reason could be that you've reached the maximum number of transactions allowed for the day. In this case, you may need to wait until tomorrow to try the same transaction again.

Note: Remember to use only business UPI accounts. You can't send money to personal UPI accounts. Stick to business accounts for your transactions.

Platform Support

Android	iOS
✔️	✔️

Getting started

Add the plugin package to the pubspec.yaml file in your project:

name: flutter_pay_upi
description: A Flutter plugin for integrating UPI (Unified Payments Interface) payments in your Flutter app.

version: 0.2.1

environment:
  sdk: '>=3.1.5 <4.0.0'
  flutter: '>=3.3.0'

dependencies:
  flutter_pay_upi: ^0.2.1 // Just add this dependency and see the magic.

flutter:
  plugin:
    androidPackage: com.example.flutterpayupi
    iosPrefix: FLT

  platforms:
    android:
      minSdkVersion: 19

Install the new dependency:

flutter pub get

Android Configuration

To get all the Upi apps:

    List<UpiApp> androidUpiList = await FlutterPayUpiManager.getListOfAndroidUpiApps();

iOS Configuration

To get all the Upi apps:

    List<UpiIosModel> androidUpiList = await FlutterPayUpiManager.getListOfIosUpiApps();

Mandatory:

Implement in your info.plist:

	<key>LSApplicationQueriesSchemes</key>
    	<array>
    		<string>phonepe</string>
    		<string>tez</string>
    		<string>paytm</string>
    		<string>gpay</string>
    		<string>BHIM</string>
    	</array>

and Lifecyle in your widget:

class FlutterPayUPI extends StatefulWidget {
  const FlutterPayUPI({super.key});

  @override
  _FlutterPayUPIState createState() => _FlutterPayUPIState();
}

class _FlutterPayUPIState extends State<FlutterPayUPI> with WidgetsBindingObserver {

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

 @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) {
      if (Platform.isIOS) {
        ///Develop a method to verify transactions, as iOS does not provide an
        ///immediate response upon successful payment. The verification process
        ///involves checking the method when the application regains focus to
        ///determine whether the transaction was successful.
      }
    }
  }
}

Note: Make a method to check if a payment was successful on iOS because iOS doesn't give an immediate response when a payment goes through. You can do this by checking the method when you return to the app to see if the payment worked.

Start Payment

    FlutterPayUpiManager.startPayment(paymentApp: upiApp.app!,
      payeeVpa: payeeVpa!,
      payeeName: payeeName!,
      transactionId: transactionId!,
      payeeMerchantCode: payeeMerchantCode!,
      description: description!,
      amount: amount!,
      response: (UpiResponse response){
        // TODO: add your success logic here
      },
      error: (e){
        // TODO: add your exception logic here
      });

Understanding code

enum used here is for UpiExceptionType you don't need to worry Just add e.toString() in error. This will print errors.

enum UpiExceptionType {
  /// when transaction is cancelled by the user.
  cancelledException,

  /// when transaction failed
  failedException,

  /// Transaction is in PENDING state. Money might get deducted from user’s account but not yet deposited in payee’s account.
  submittedException,

  /// Transaction is in PENDING state. Money might get deducted from user’s account but not yet deposited in payee’s account.
  appNotFoundException,

  /// when unknown exception occurs
  unknownException,
}

Note: If you want inbuilt gridview. just add this code:

UPIAppList(onClick: (upiApp) async {
    FlutterPayUpiManager.startPayment(
        paymentApp: upiApp.app!,
        payeeVpa: payeeVpa!,
        payeeName: payeeName!,
        transactionId: transactionId!,
        payeeMerchantCode: payeeMerchantCode!,
        description: description!,
        amount: amount!,
        response: (UpiResponse response) {
          // TODO: add your success logic here
        },
        error: (e) {
          // TODO: add your exception logic here
        print(e.toString());
        });
}),

Behaviour, Limitations & Measures

Android

Flow

• On Android, UPI Deep Linking and Proximity Integration is achieved using Intents.
• When initiating a transaction, an Intent call is made with transaction details, specifying the UPI app to use.
• After processing the UPI transaction in the chosen app, it sends back a response following the specification format.
• The Android plugin layer of the package handles this response.
• The plugin layer parses the response to create a UpiResponse object.
• This object clearly indicates the status of the UPI payment—whether it was successful, failed, or is still being processed.
• The UpiResponse object is then returned to your calling code for further handling.

Measure

It's recommended to add an extra layer of security by setting up a server-side payment check. This helps protect against potential issues or hacks in the UPI transaction process on the user's phone.

iOS

Flow

• Each UPI payment app can respond to a payment request with a format like "upi://pay?..." sent by another app on iOS.
• The specification doesn't let you specify which UPI app to use in the request.
• iOS doesn't provide a way to choose a specific UPI app or to know which one will be used.
• When you send the request, one of the installed UPI apps on the iPhone will handle it and process the payment.
• Unfortunately, the system doesn't allow the UPI app to inform your code about the transaction status.
• Your code can only determine if the UPI app was successfully launched or not.

Measures

• Implement payment verification on the existing package functionality.
• Distinguish between discovered and supported-only apps using the mentioned method.
• Use the Example as a reference.

Supported Apps

• Amazon Pay
• BHIM
• Google Pay
• Paytm
• PhonePe

Reference

Reference took from EasyUpiPayment-Android by shreyas Patil.

This code was helpful to you

License

MIT License

Copyright (c) 2023 Abhishek Bardolia

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